A lubricant composition containing diethylenetriaminepentaacetic acid as a corrosion inhibitor

Abstract

An embodiment of a lubricant composition that may include an oil lubricant and a corrosion inhibitor, wherein the corrosion inhibitor may be diethylenetriaminepentaacetic acid (DTPA).

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of U.S. Provisional Application No. 63 / 359,591, filed Jul. 8, 2022, which is hereby incorporated by reference in its entirety.

[0002] Embodiments described herein generally relate to corrosion prevention, and more specifically, to lubricant compositions containing corrosion inhibitors.

Background Art

[0003] Acid copolymer resin (ACR) can be used, inter alia, to manufacture packaging materials, building panels, and water pipes. As a result of this utility, there is a worldwide demand for ACR. ACR production often involves the use of corrosive materials. Over time, these corrosive materials can corrode the components of the ACR production system, requiring replacement of these components. The replacement of these components can increase the cost of ACR production. Therefore, it is necessary to improve ACR production, and more specifically, to improve the protection of the ACR production system from the effects of corrosion.

Summary of the Invention

[0004] Embodiments of the present disclosure meet this need by including diethylenetriaminepentaacetic acid (DTPA) in a lubricant composition to inhibit corrosion.

[0005] According to one or more embodiments of the present disclosure, a lubricant composition is provided. The lubricant composition includes an oil lubricant and a corrosion inhibitor, and the corrosion inhibitor is DTPA.

[0006] Additional features and advantages are described in the following "Detailed Description of the Invention", and some will be readily apparent to those skilled in the art from that description, or will be recognized by practicing the embodiments described in this specification, including the drawings, the following "Detailed Description of the Invention" and the "Claims".

Brief Description of the Drawings

[0007]

Figure 1

[0008] When explaining the simplified schematic diagram of FIG. 1, numerous valves, temperature sensors, electronic controllers, etc. that can be used and are well known to those skilled in the art are not included. However, it should be understood that these components are within the scope of the present disclosure.

[0009] Here, various embodiments are referred to in more detail, some of which are illustrated in the accompanying drawings.

Modes for Carrying Out the Invention

[0010] Here, specific embodiments of the present application are described. However, the present disclosure may be embodied in different forms and should not be construed as limited to the embodiments described in the present disclosure. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the subject matter to those skilled in the art.

[0011] The present disclosure relates to a lubricant composition. For example, as described herein, the lubricant composition may include a lubricating oil and a corrosion inhibitor. The corrosion inhibitor may be DTPA. Such a lubricant composition containing DTPA may be particularly suitable for use in a free radical polymerization process in which a bronze packing ring is utilized in a compressor.

[0012] In one or more embodiments, the lubricant composition may include an oil lubricant. The oil lubricant may include at least one oil and may include one or more additives, for example, one or more lubricants. Additives may be added to improve lubricity, flow characteristics, thermal stability, and / or other properties. In one or more embodiments, at least one oil may be a petroleum-derived viscous liquid having an increased viscosity compared to the viscosity of water at the same temperature and pressure. At least one oil may provide lubrication and friction reduction between the movable surfaces of a rotating and / or reciprocating mechanism. In one or more embodiments, the oil may be one or more mineral oils and polyalkylene glycol base oils.

[0013] In some embodiments, the oil may have a kinematic viscosity at 40 °C of 50 mm 2 / s to 200 mm 2 / s. For example, the oil may have a kinematic viscosity of 50 mm 2 / s to 100 mm 2 / s, 100 mm 2 / s to 150 mm 2 / s, 150 mm 2 / s to 200 mm 2 / s, or may have a kinematic viscosity of any combination of these ranges.

[0014] As described herein, in one or more embodiments, the lubricant composition may include a corrosion inhibitor. In some embodiments, the lubricant composition may include a corrosion inhibitor in an amount of 0.5 wt% to about 20 wt%. For example, the lubricant composition may include the corrosion inhibitor in an amount of 0.5 wt% to 1 wt%, 1 wt% to 5 wt%, 5 wt% to 10 wt%, 10 wt% to 15 wt%, 15 wt% to 20 wt%, or any combination of these ranges. In some embodiments, the lubricant composition may include the corrosion inhibitor in an amount of 1 wt% to 17.5 wt%, 1.5 wt% to 15 wt%, 2 wt% to 12.5 wt%, or 2.5 wt% to 10 wt%. In some embodiments, the lubricant composition may include DTPA in an amount of 2.5 wt% to 10 wt%.

[0015] In one or more embodiments, the lubricant composition can be used in a method of reducing corrosion that includes exposing a metal part to a solution containing the lubricant composition and (meth)acrylic acid, and the lubricant composition reduces metal corrosion. As used in this disclosure, the term "(meth)acrylic acid" can be used to refer to either methacrylic acid, acrylic acid, or both.

[0016] In one or more embodiments, the solution containing the lubricant composition can include a co-solvent. The co-solvent can include a carboxylic acid, an alcohol, or a combination thereof. In some embodiments, the co-solvent can include methanol.

[0017] In one or more embodiments, the metal part can include a bronze packing ring. In one or more embodiments, the bronze packing ring can be part of a compressor. In some embodiments, the bronze packing ring can be part of a compressor unit utilized within a high-pressure polyethylene reactor such as that schematically shown in FIG. 1.

[0018] In one or more embodiments, the lubricant composition can be used in a free-radical polymerization process that includes polymerizing ethylene monomer and optionally (meth)acrylic acid in the presence of the lubricant composition via free-radical polymerization within a high-pressure polyethylene reactor having a compressor equipped with a bronze packing ring. The free-radical polymerization process for the production of ethylene-based polymers is typically carried out at high pressure, typically at least 100 MPa. For example, the free-radical polymerization process can be carried out at least 200 MPa, at least 300 MPa, at least 400 MPa, or at least 500 MPa.

[0019] The following definitions can be helpful in understanding the operation of an exemplary reactor system that may be suitable for use with the lubricant compositions described herein.

[0020] As used herein, the terms "feed" or "feed stream" refer to fresh and / or recycled reactants added to the reaction zone at the inlet.

[0021] As used herein, the term "reaction zone" refers to a reactor zone where a polymerization reaction is initiated or restarted by the addition of free radicals and / or by decomposition into free radicals or components that generate free radicals.

[0022] As used herein, the term "reactor system" refers to the components (equipment) used to polymerize and isolate a polymer. Such components / equipment include, but are not limited to, one or more reactors, a hypercompressor, a primary compressor, and a booster compressor. The reactor system typically includes at least one reactor, such as a tubular reactor, an autoclave reactor, or any combination thereof.

[0023] As used herein, the term "injection point" refers to the location of the inlet of the equipment (used in the polymerization process) where the feed stream is added to the equipment.

[0024] As used herein, the term "pressurize" refers to increasing the pressure of a liquid or a feed to a higher pressure level.

[0025] As used herein, the term "compression system" refers to a compression device that increases the pressure of a vapor (e.g., ethylene vapor below or above its critical point) to a higher pressure level. Supplying a comonomer can include directly pressurizing and supplying the reactive comonomer to the reaction zone and / or the feed stream to the reaction zone with an ultra-high pressure reciprocating plunger pump, and / or supplying the comonomer by a combination of pressurization with a high-pressure pump and further compression via a reciprocating plunger compressor (e.g., a hypercompressor, a primary compressor, and / or a booster compressor).

[0026] As used herein, the term "compression" refers to increasing the pressure of a vapor (e.g., ethylene vapor below or above its critical point) to a higher pressure level.

[0027] A booster compressor is, for example, a device that compresses the low-pressure recycle stream flowing in from a low-pressure separator to the pressure level required at the inlet side of the primary compressor. This compression can be carried out in one or more compression stages and can be combined with intermediate cooling. The booster compressor can consist of a single or multiple compressor frames and can potentially be combined with the primary compressor frame.

[0028] The primary compressor is, for example, a device that compresses: a) fresh incoming ethylene, and / or b) the low-pressure recycle stream flowing in from the booster compressor, each to the pressure level required at the inlet side of the hypercompressor. This compression can be carried out in one or more compression stages and can be combined with intermediate cooling. The primary compressor can consist of a single or multiple compressor frames and can potentially be combined with the booster compressor frame.

[0029] The hypercompressor, or secondary compressor, is, for example, a device that compresses the monomer flowing in from the primary compressor to the pressure level required for supply to the reactor at its inlet pressure setpoint. This compression can be carried out in one or more compression stages and can be combined with intermediate cooling. The hypercompressor typically includes a piston reciprocating compressor and can consist of a single or multiple compressor frames.

[0030] Referring now to FIG. 1, an exemplary reactor system that may be suitable for use with the lubricant compositions described herein is schematically shown. It should be understood that not all parts of FIG. 1 are to be construed as essential to the claimed subject matter. Further, although the lubricant compositions in the appended claims are described herein in the context of FIG. 1, such listed compositions are to be understood as adaptable to other systems as would be understood by one of ordinary skill in the art.

[0031] Figure 1 shows a generalized flow schematic of a high-pressure polymerization process including a reactor 26 that can be a tubular reactor, an autoclave reactor, or a combination of both a tubular reactor and an autoclave reactor. Stream (1) represents a fresh ethylene composition that is compressed by a primary compressor (22) along with the outlet of a booster compressor (20) into stream (2). The fresh monomer composition may include ethylene. Stream (2) is combined with a high-pressure recycle stream (7) from a high-pressure separator (28) of a hypercompressor inlet stream (3) and fed to the suction inlet of a hypercompressor (24). The hypercompressor compresses the ethylene feed stream to a level sufficient to supply the reactor (26). Stream 4 represents the compressed monomer feed stream supplied to the reactor (26). The high-pressure separator (28) separates the product stream (5) into a polymer-rich stream (6) and an unreacted monomer-rich stream (7). Stream (7) is recycled for reuse in the process, and stream (6) is sent to a low-pressure separator (30). The low-pressure separator (30) separates the vapor (6) into a monomer stream (8) flowing to the booster compressor (20) and a polymer stream (9) withdrawn for further processing.

[0032] In one or more embodiments, the lubricant compositions described herein can be utilized in a hypercompressor (24). For example, a lubricant composition comprising an oil lubricant and a corrosion inhibitor including DTPA can be exposed to the metal parts of the hypercompressor (24). In some embodiments, the metal parts of the hypercompressor (24) can include bronze packing rings.

[0033] Test Methods Corrosion Test The corrosion test is at 20 °C and 8.8 g / cm 3It was carried out using 936 bearing bronze coupons having a density of. The bronze coupons were cut to a diameter of 1.27 cm and a thickness of 0.32 cm. The tests were conducted inside a glove box. The reagents were degassed and dried as necessary before being placed in the glove box. All experiments were repeated 5 times and the averages were reported. The pre-measured coupons were added to 40 mL vials equipped with pressure relief caps. Then, the reagents were added to the vials and the pressure relief caps were fixed. Then, the vials were removed from the glove box and photographs of the vials were taken. Then, the vials were placed in a heating block and heated at 100 °C for 2 weeks. After 2 weeks, the vials were removed from the heating block and cooled. When the vials had cooled to room temperature, the coupons were removed from the vials using tweezers and placed on a chemwipe. The coupons were rinsed with tetradecane on a metal pan and wiped completely with a metal spatula. The flat end of the spatula was used at an angle of approximately 30° to scrape off any corrosion or deposits on the surface of the coupon. Care was taken not to apply maximum pressure to the coupon while scraping so that the surface of the coupon was not gouged. The coupons were rinsed with clean tetradecane and wiped with a chemwipe. The washed coupons were placed in separate 20 mL vials each. The vials containing the washed coupons were placed in a vacuum oven at 160 °C overnight to dry. Then, the dry coupons were weighed. The difference between the dry coupon weight and the starting coupon weight was measured and recorded.

[0034] Corrosion rate The corrosion rate was measured using the following formula: where the weight loss is the difference between the dry coupon weight and the starting coupon weight, the alloy density is 8.8 g / cm 3 and the exposed area of the coupon was measured by considering the coupon as a cylinder, and the exposed area was calculated as the area of the cylinder. The coupon had a diameter of 1.27 cm and a thickness of 0.32 cm for an exposed area of 3.86 cm 2 The exposure time was 336 hours, and K is the K factor. The alloy density and K factor values were collected from the literature.

[0035]

Number

[0036] Corrosion prevention Corrosion inhibition was measured and the percentage of corrosion inhibition was calculated using the following formula. The corrosion rate not inhibited was calculated from the corrosion rate of the coupon in the absence of the inhibitor. The inhibited corrosion rate was calculated from the corrosion rate of the coupon to which the inhibitor was added.

[0037]

Number

Example

[0038] The embodiments will be further clarified by the following examples.

[0039]

Table 1

[0040] Table 1 shows the composition of the lubricant compositions tested for corrosion prevention performance. A corrosion inhibitor test was conducted using formulations having lubricating oil, methanol, methacrylic acid, and optionally a corrosion inhibitor. The lubricating oil used was Hydrobrite 380, a commonly available white mineral oil manufactured by Sonneborn. The inhibitors used were diethylenetriaminepentaacetic acid (DTPA) and ethylenediaminetetraacetic acid (EDTA). The amount of inhibitor added in each experiment was calculated as a weight percentage of the Hydrobrite 380 lubricating oil.

[0041]

Table 2

[0042]

Table 3

[0043] Referring to the corrosion inhibition test results in Tables 2 and 3, the experiments with DTPA (i.e., Experiments 2-4) have significantly higher corrosion inhibition and significantly less weight loss due to corrosion than comparative examples without DTPA, such as Comparative Examples A and B. Briefly, Tables 2 and 3 show that DTPA exhibited superior corrosion inhibition against methanol and methacrylic acid when combined with lubricating oils. Without being limited by theory, it is believed that the DTPA structure confers improved hydrophobicity compared to EDTA, which is partially correlated to improved corrosion resistance.

[0044] In a first embodiment of the disclosure, a lubricant composition can include an oil lubricant and a corrosion inhibitor, wherein the corrosion inhibitor is diethylenetriaminepentaacetic acid.

[0045] A second aspect of the present disclosure may include the first aspect, wherein the oil lubricant comprises a mineral oil.

[0046] A third aspect of the present disclosure can include any of the previous aspects, where the lubricant composition includes 0.5% to 20% by weight of the corrosion inhibitor, or 2.5% to 10% by weight of the corrosion inhibitor.

[0047] A fourth aspect of the disclosure may include a method for reducing corrosion comprising exposing a metal part to a solution comprising the lubricant composition of any of the preceding aspects and (meth)acrylic acid, wherein the lubricant composition reduces metal corrosion.

[0048] A fifth aspect of the present disclosure may include the fourth aspect, wherein the solution may include a co-solvent.

[0049] A sixth aspect of the present disclosure may include the fifth aspect, wherein the co-solvent comprises a carboxylic acid, an alcohol, or a combination thereof.

[0050] A seventh aspect of the present disclosure may include the sixth aspect, wherein the alcohol includes methanol.

[0051] An eighth aspect of the present disclosure may include any of the fourth to seventh aspects, in which the metal part includes a bronze packing ring.

[0052] The ninth aspect of the present disclosure may include the eighth aspect in which the bronze packing ring is part of a compressor.

[0053] The tenth aspect of the present disclosure may include the eighth aspect in which the bronze packing ring is part of a compressor unit used in a high-pressure polyethylene reactor.

[0054] The eleventh aspect of the present disclosure may include a free-radicalization process that includes polymerizing ethylene monomer and optionally a (meth)acrylic acid comonomer in the presence of a lubricant composition according to any of the first to third aspects via free-radical polymerization in a high-pressure polyethylene reactor having a compressor equipped with a bronze packing ring.

[0055] It will be apparent to those skilled in the art that various modifications and changes can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Accordingly, this specification is intended to cover such modifications and changes to the various embodiments described herein, provided that such modifications and changes fall within the scope of the appended claims and their equivalents.

[0056] For the purpose of defining the technology, the transitional phrase "consisting of" may be introduced into the claims as a closed - preamble term that limits the claims to the recited components or steps and any naturally occurring impurities. For the purpose of defining the technology, the transitional phrase "consisting essentially of" may be introduced into the claims to limit one or more claims to the recited elements, components, materials, or method steps, and any unrecited elements, components, materials, or method steps that do not substantially affect the novel features of the claimed subject matter. The transitional phrases "consisting of" and "consisting essentially of" can be interpreted as subsets of open - ended transitional phrases such as "comprising" and "including", and as a result, any use of an open - ended phrase to introduce a listing of a series of elements, components, materials, or steps should be interpreted as also disclosing a listing of a series of elements, components, materials, or steps using the closed terms "consisting of" and "consisting essentially of". For example, a description of a composition "comprising" components A, B, and C should be interpreted as also disclosing a composition "consisting of" components A, B, and C, and a composition "consisting essentially of" components A, B, and C. Any quantitative value expressed in this application can be considered to include open - ended embodiments that are consistent with the transitional phrase "comprising" or "including", as well as closed or partially closed embodiments that are consistent with the transitional phrases "consisting of" and "consisting essentially of".

[0057] As used in this specification and the appended claims, the singular forms "a", "an", and "the" include the plural referents unless the context clearly dictates otherwise. The verb "comprises" and its conjugations are to be construed as referring to elements, components, or steps in a non-exclusive manner. The recited elements, components, or steps may be present, utilized, or combined with other elements, components, or steps not expressly recited.

[0058] It is to be understood that any two quantitative values assigned to a characteristic may constitute a range of that characteristic, and all combinations of ranges formed from all the recited quantitative values of a given characteristic are contemplated in the present disclosure. The subject matter of the present disclosure has been described in detail with reference to specific embodiments. It is to be understood that any detailed description of any component or feature of an embodiment does not necessarily imply that such component or feature is essential to that or any other embodiment. Further, it should be apparent to those skilled in the art that various modifications and changes can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter.

Claims

1. A lubricant composition comprising an oil lubricant, and a corrosion inhibitor, wherein the corrosion inhibitor is diethylenetriaminepentaacetic acid (DTPA).

2. The lubricant composition according to claim 1, wherein the oil lubricant comprises mineral oil.

3. The lubricant composition according to claim 1 or 2, wherein the lubricant composition comprises 0.5% to 20% by weight of the corrosion inhibitor, or 2.5% to 10% by weight of the corrosion inhibitor.

4. A method for reducing corrosion, comprising exposing a metal part to a solution comprising the lubricant composition according to any one of claims 1 to 3 and (meth)acrylic acid, wherein the lubricant composition reduces metal corrosion.

5. The method according to claim 4, wherein the solution may comprise a co-solvent.

6. The method according to claim 5, wherein the co-solvent comprises a carboxylic acid, an alcohol, or a combination thereof.

7. The method according to claim 6, wherein the alcohol comprises methanol.

8. The method according to any one of claims 4 to 7, wherein the metal part comprises a bronze packing ring.

9. The method according to claim 8, wherein the bronze packing ring is part of a compressor.

10. The method according to claim 8, wherein the bronze packing ring is part of a compressor unit used in a high-pressure polyethylene reactor.

11. A free radical polymerization process comprising polymerizing an ethylene monomer and optionally a (meth)acrylic acid comonomer in the presence of the lubricant composition according to any one of claims 1 to 3 via free radical polymerization in a high-pressure polyethylene reactor having a compressor equipped with a bronze packing ring.

Images